1. Field of the Invention
The present invention relates to a lightweight door of a vehicle which is easy to assemble and comprises a decreased number of parts and a method of assembling the door.
2. Description of the Related Art
Typically, vehicle doors are made up of a door panel assembly comprising a steel inner door panel and a steel outer door panel to which various functional parts and devices, such as a window regulator and a door lock/unlock mechanism, are directly mounted. In recent years, in order to decrease the number of internal constituent parts of such a vehicle door and to lighten such a door, it has been proposed to use a plastic panel to which various functional parts and devices are mounted. The plastic panel is attached to the steel inner door panel such that it closes up an opening of the inner door panel. One of the vehicle doors is known from, for example, Japanese Unexamined patent application No. 9-157374.
Because using the plastic mounting panel Prepared separately from the door panel assembly allows the inner door panel to take even various complicated forms without restraint, it is possible to eliminate fixing members such as clips that are used to fix internal constituent parts and devices to the door panel assembly. Further, because using the plastic panel allows internal constituent parts and devices to be disposed at various locations, a significant effect is produced in terms of increasing the degree of freedom for laying out the internal constituent parts
The plastic panel is formed by press molding or injection molding. In the case where one piece panel member is used to form the almost entire part of the inner door panel as disclosed in Japanese Unexamined patent application No. 9-157374, it is almost inevitable that the inner door panel is large in size. In consequence, when using a plastic panel member that is attached to a door panel assembly, a large size of mold is necessary. This needs a large amount of plastic material and results in application of considerably high molding pressure or injection pressure. It is undesirable to use a large size of molding equipment and a large amount of material for simply preparing the one piece plastic panel in light of production efficiency.
It is therefore an object of the present invention to provide a vehicle door which includes a plastic panel to be installed thereto, the plastic panel being formed with high efficiency of production
It is another object of the present invention to provide a process of assembling a vehicle door which includes a plastic panel installed to the vehicle door, with high efficiency of assembling.
The above objects of the present invention are accomplished by a vehicle door comprising an outer door panel, and an inner door panel formed wit an aperture, a mounting panel to which functional devices of the vehicle door and door parts are mounted and which is installed to the inner door panel to close up the aperture of the inner door panel. The mounting panel comprises a plastic panel formed in conformity with the aperture of the inner door panel, a plastic structural part appedant to the plastic panel, and a breakable joint connecting the plastic structural part to the plastic panel which are formed as one piece by, for example, injection molding. The plastic structural part is separated from the plastic panel by breaking away the joint from the plastic panel during installing work of the mounting panel to the inner door panel.
The plastic structural part is one of the door parts that are mounted or fitted to the mounting panel, such as a cover for covering an opening formed in the plastic panel which provides an access to the inside of the vehicle door for assembling the vehicle door. The plastic structural part is mounted or fitted to the plastic panel desirably after installation of the plastic panel to the inner door panel.
The inner door panel has a substantial wall section forming part of a side wall of a passenger compartment of the vehicle and the plastic structural part before separation from the plastic panel occupies a location where it overlaps the substantial wall section of the inner door panel when the mounting panel is installed.
According to the vehicle door of the present invention, the plastic mounting panel is formed as one piece including a structural part which is separated from the plastic mounting plate and installed to the plastic mounting panel after having been assembled to the vehicle door. This configuration of the plastic mounting panel enables putting a large amount of plastic material and a large size molding apparatus to efficient use, so as to increase the productivity of the mounting panel.
Owing to the configuration of the plastic mounting panel that the plastic structural part before separation from the plastic panel occupies a location where it overlaps the substantial wall section of the inner door panel when the mounting panel is installed, while the plastic mounting panel is formed so as to have the plastic panel in conformity with the aperture of the inner door panel, the plastic structural part is formed as one of the door parts at a location where the plastic panel is in non-occupation. As a result, the plastic mounting panel can be configured in the form of substantially rectangular flat plate, so tat it is easy to pile up a number of the plastic mounting panels and to convey a stack of the plastic mounting panels safely and reliably, without separating the appendant parts. For example, in the case where the plastic panel has a shape like a generally rectangle with one of the corners cut off, the plastic structural part is formed in a generally rectangular panel by locating the plastic structural part as an appedant part to the plastic panel at the cutoff corner. Moreover, because the plastic structural part is one of the door parts that be installed to the mounting panel, the plastic structural part can be always along with the plastic panel until the plastic panel is installed to the door panel and is separated from the plastic panel immediately before the plastic structural part is intended to be installed to the plastic panel. In consequence, it is not feared that the plastic struck part is missing before assembling such as during conveyance thereof.
In the case where the plastic structural part is formed as a cover for covering an opening formed in the plastic panel which provides an access to the inside of the vehicle door for assembling the vehicle door, the plastic structural part is always along with the plastic panel until the assembling work is finished, so as to make it reliable to cover the access opening in the plastic panel, thereby completing the vehicle door.
According to the process of assembling the vehicle door of the present invention, the plastic struck part is separate and then installed to the plastic panel during assembling work of the vehicle door or after the plastic panel has been installed to the door panel. Desirably, the plastic structural part is separated and then installed to the plastic panel after having installed the plastic panel to the door panel. In consequence, the plastic structural part is always along with the plastic panel until the assembling work is finished, so that it is not feared that the plastic structural part is missing before assembling such as during conveyance thereof, which makes it reliable to install the plastic structural part to the plastic panel in order to complete the vehicle door. The process eliminates the fear that the plastic structural part is missing and provides reliable installation of the plastic structural part to the plastic panel.